The present invention relates to diode laser collimatting devices and relates more particularly to a diode laser collimatting device which can be conveniently assembled to provide a fixed focal length.
Laser diode has been widely used in light collimatting devices. For example, in laser sighting devices and beacon pens, laser diode has been commonly used as a light emitting element. FIG. 1 illustrates a diode laser collimatting device according to the prior art which is generally comprised of a laser collimatting socket (1) having a lens (3), which is made from glass material, fastened in a light collimatting hole (2) through the central axis thereof, and a socket holder (5) having a laser diode (7) fastened therein. The laser collimatting socket (1) has an outer thread (4) inserted into an inner thread (6) on the socket holder (5). By rotating the laser collimatting socket (1) on the socket holder (5), the focal length of the diode laser collimatting device is adjusted. If a lens is made from glass material it should be treated through manual grinding process so as to provide a smooth surface for focusing. Therefore, the focal length of one lens may vary with another. After assembly, the focal length of each diode laser collimatting device must be properly adjusted. As indicated, the lens (3) and the laser diode (7) are respectively fastened in two separate parts, namely, the laser collimatting socket (1) and the socket holder (5), the lens (3) and the light beam from the laser diode (7) may have different concentricity which affects the focusing of the lens (3). Further, according to the property of laser diode in emitting a light, the image produced from a laser diode covers 6.degree.-10.degree. horizontally and 20.degree.-40.degree. vertically, i.e. the image disperses outwards like a transverse strip, and the size of the image is directly proportional to the distance from the laser diode. In order to focus the whole image from a laser diode, bigger lens shall be used. Using a bigger lens in a diode laser collimatting device simultaneously increases the cost of the device.
The present invention has been accomplished to eliminate the aforesaid problems. It is therefore the main object of the present invention to provide a diode laser collimatting device which is inexpensive to manufacture and easy to assemble. It is another object of the present invention to provide a diode laser collimatting device which is practical in use without adjusting focal length and is water-proof and shock-resisting.